A method pertaining to an SCR system for exhaust cleaning, includes deciding about a need, after cessation of an exhaust flow, to cool a reducing agent dosing unit (250) by a reducing agent supplied to it, and includes predicting a temperature pattern of the dosing unit (250) as a basis for deciding about the need and predicting whether a predetermined temperature of the dosing unit will be reached after cessation of exhaust flow. Also a computer program product containing program code (P) for implementing the method, an SCR system and a motor vehicle which is equipped with the SCR system are disclosed.